1. Field of the Invention
The present invention relates to a device for securing an actuator rod into a locked position which is utilized for locking a valve actuation rod with motor during transport.
2. Description of the Related Art
A motor in which a spring returns and thereby closes the valve during a power outage is referred to as a motor with safety actuation.
The safety device-for safety actuation should close the valve with a predetermined force. Since the valve actuating rod is pretensioned, the safety device will extend farther than the required valve travel when the motor is not installed in the valve. Consequently, a motor can not be installed in a valve in this position without sustaining mechanical damage.
According to a first possible design, the aforedescribed motor is installed by powering the motor up at the valve manufacturer""s site before the installation, whereby the valve actuating rod is retracted and thus installed in this position. The motor can subsequently be operated normally.
According to a second possible design, the valve actuating rod is retracted at the manufacturer""s site by operating the motor and then secured in position by a separate stop motion device (which represents an additional throw-away part). The motor must be energized before installation, the additional part removed, and the motor can be installed in the energized state.
It is an object of the invention to provide a locking device for safety actuation of a valve drive with a motor wherein the position of the actuator rod can be reliably set when the motor is transported and installed without the need to power the motor or to use an additional throw-away part.
A solution of this object according to the invention is provided by a device suitable for securing the position of the valve actuating rod of a motor with safety actuation. Accordingly, the valve actuating rod can be locked in a position suitable for assembly or transportation by implementing a flexible locking element, which is secured to the valve cone positioned on the actuating rod. The locking element engages with a recess of guide mechanism attached to the motor housing in a formfitting way to lock the actuating rod into position. In the alternative, upon retracting the actuating rod with the valve cone, the locking element disengages from the recess of the guide mechanism and the actuating rod is in a released state.
The invention is based on the concept of securing an resilient locking or latching element to the valve cone of the valve actuating rod, wherein in the desired installation position the locking or latching element is in force-transmitting engagement with the guide mechanism of the actuating rod so as to fix and lock the actuating rod in position or, alternatively, engages in a formfitting manner with a recess of the guide mechanism of the actuating rod.
To fix or secure the actuating rod in position in a force-transmitting or formfitting manner, the motor is powered until the valve actuating rod is sufficiently retracted. Subsequently, a mechanical connection is established between the resilient locking element and the guide mechanism of the actuating rod. After the motor is installed, the actuating rod is unlocked and released by further retracting the valve actuating rod 5. The locking element may also have a catch which extends tangentially, or radially inwardly or outwardly.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are intended solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.